C6 Root of the Brachial Plexus, Lateral View

Description

Arising from the C6 spinal nerve within the interscalene interval, the C6 root courses laterally between the anterior and middle scalene muscles, posterior to the sternocleidomastoid and superior to the clavicle. From a lateral neck perspective, the root can be followed as it joins the C5 root to form the superior trunk of the brachial plexus, lying superior and posterior to the subclavian artery as the plexus approaches the first rib. Nearby vascular landmarks commonly visible in this angle include the internal jugular vein and common carotid artery within the carotid sheath, positioned anteromedial to the scalene triangle. This specific segment matters because the C5 to C6 elements anchor the superior trunk, the structure injured in classic Erb-Duchenne palsy after traction that increases the angle between neck and shoulder. Orientation to the anterior scalene is also procedural, the C6 level is a frequent target for interscalene brachial plexus block, where needle trajectory and spread determine whether anesthesia favors shoulder surgery while risking phrenic nerve involvement on the anterior scalene. Small distances. Big consequences. Use this illustration for teaching cervical root and trunk organization in gross anatomy, regional anesthesia modules, and upper limb neuroanatomy courses that emphasize surface landmarks and fascial compartments. It also supports surgical atlas content on supraclavicular exposure of the plexus and educational material on traction neuropathies and radiculopathy patterns involving C6. Anatomical accuracy verified by SciePro's Medical Advisory Board.